Hs 


I  Hi 


hifertjf  if  the  lioiid  Slates  Scvernmscl 


ClRCULAH   No.    105 


United  States  Ik'ii.irtni^Mjf^toitilt 


BUREAU   OF    HNT 

L.  O    HOWAHI).   Kntomologist  a 


III  i:  ROSE  si. I  <;s. 

r.v  r.  ii.  < 'hi  1 1 1  mm  \. 
In  Chargt  of  Truck  Crop  <tmi  Special  //;>..'  In  mitigations. 

lioses  grown  in  gardens  in  the  United  States  are  attacked  by  three 
species  of  sawflies  which  live,  in  their  larval  stages,  on  the  foliage, 
skeletonizing  the  leaves  or  cutting  out  holes  of  variable  size  and 
greatly  disfiguring  the  plants.  The  larva?,  popularl}  know  n  as  "  i 
slogs,"  "  slugworms,"  and  "roseworms,"  have  been  classified  as  the 
American  rose  >\\\n\  the  bristly  roseworm,  and  the  coiled  or  curled 
roseworm,  respectively.  For  the  sake  of  uniformity  they  may  all  be 
called  rose  slugs.  The  first  of  these,  ;i-  ii-  common  name  indicates, 
i-  native  t<>  America;  the  other  two  are  evidently  accidental  intro 
ductions  from  Europe,  ;i-  they  are  now  common  in  I >< >t  1 1  hemispheres. 
\  with  1 1 1 « »- 1  other  sawflies,"  they  are  found  more  abundantly  in  the 
North,  but  are  quite  troublesome  as  far  southward  ;i>  Maryland  and 
Kansas.     They  practically  confine  their  depredations  t<>  the  flower 

;  >lcn.  ;in«l  roses  are  the  only  plants  thai  are  seriously  damaged  l>v 
them.  Injury  i-  due  entirely  t<>  the  larva?,  and  the  three  species,  each 
representing  a  distinct  genus,  differ  considerably  in  appearance  in  all 
stages,  as  also  in  their  life  history  and  manner  of  work. 

THE  AMERICAN  ROSE  SLUG. 
rf<  him  uiii  1 08a  I  tarr.  < ' 

The  American  rose  slug  was  firsl  identified  as  ;i  pest  about  the  year 
1831,  when  it  *  1  i « I  damage  in  gardens  at  Cambridge,  Mass.  At  that 
time  the  species  was  somewhat  restricted  to  that  locality,  but  later, 
according  to  Harris,  who  observed  and  studied  it-  habits,  it  grad- 
ually spread  in  that  vicinity  and  by  1840  it  hud  become  so  great  a 
nuisance  that  :i  premium  of  $100  was  offered  for  the  most  successful 
method  of  destroying  it. 


"  Hymeuopterous  Insects  of  the  family  TeolkmHuldse 
*  Synonyms :   Uonostcgia  rosa  ■•;:•]  Sclandnia  rosa" 
Bepon  Ins.  <>f  M..-<s.  inj.  to  Veget.,  1841,  i 
5411B     Clr.  L06    06 


52$. 


DESCRIPTIVE. 


The  sawfly  which  produces  the  American  rose  slug  is  a  four-winged 
bee-like  insed   (fig.  1.  a)  of  a  deep  shining  black  color,  with  tran- 
luccnt  smoky  wings  having  dark-brown  veins  and  a  brown  spot  near 
die  middle  of  the  edge  of  the  forewings.     The  wing  expanse  of  the 
female  is  about   two-fifths  of  an   inch  and  the  length  of  the  bod  \ 
fully  one-fifth  of  an  inch.    The  male  is  a  little  smaller. 

The  larva  or  slug  (A.  figs.  1.  2)  when  full  grown  is  about  one-third 
of  an  inch  long  and  sluglike,  with  the  thoracic  joints  enlarged.     The 


Fig.  1. — American  rose  slug  (Endelomyia  rosw)  :  n,  Adult  sawfly;  b.  mature  larva;  c, 
work  of  larvae  on  rose  leaf;  <l,  section  of  rose  leaf,  Showing  location  of  egg  near  upper 
margin  ;  e,  egg  in  situ  on  bit  of  rose  leaf,  o,  '».  e,  Much  enlarged  :  o,  loss  enlarged  ;  d, 
about  natural  size.      (  Original,  i 

body  is  soft  and  delicate,  but  not  gelatinous  and  slimy,  as  is  the  case 
with  some  sawfly  larvae — for  example,  the  pear  slug.  The  color  is 
green  above  and  yellowish  on  the  lower  surface.  The  head  (fig.  2,  c) 
is  small,  oval,  and  yellowish,  and  has  a  black  spot  on  each  side, 
inclosing  the  eye. 

DISTRIBUTION. 


The  assertion  has  been  made  by  Riley  "  that  this  sawfly  undoubtedly 
originated  in  NewT  England,  where  it  fed  upon  wild  rose.  With  the 
lapse  of  years,  if  we  assume  this  statement  to  be  correct,  it  has  been 
disseminated  by  commerce  into  neighboring  States  and  through  the 


° American  Entomologist.  Vol.  Ill,  1880,  p.  115. 


[Cir.  105] 


3 


importation  <>f  rose  bushes  rrom  eastern  nurserie  to  '■  tern  gardens. 
Owing  to  the  sluggish  habits  of  the  female,  its  distribution  l>\  flight 
has  undoubtedly  be6n  rorj  slow.     Ii    occurrence  in  Nev    York,  Sen 

p,  Ohio,  Illinois,  Michigan,  and  Missouri  ha    been  known  for  a 
number  of  year  .  and  it  undoubtedly  occupies  intervening  States, 

In  1904  we  received  reports  of  injuries  bj   il  in  Pennsylvania,  New 
York,  Maryland,  and  Kansas;  In  that  year  it  also  appeared  :it  Char 

ville,  Va.,  and  the  following  May  reached  the  District  of  Colum 
bia,  where  it  has  been  quite  abundant  since.     In  1908  il  was  reported 
injurious  :ii  ( !incinna1  i.  <  )li i< >. 


< ... 


W 


I 


I 


CL 


'  >v 


Pifl    -.      American   rose  ^in_-   [Entleloi  ,.  r  larva  al 

work  on  upper  .  lower  lai  under  surface;  '..  larva, 

rtew,  enlarged;  e,  head  of  iirv.i.  more  enlarged      I  Original  i 

Ml  l     HISTORY. 


The  parent  sawflies  issue  from  the  earth  at  varying  time-  from 
about  the  Lsl  of  April,  or  earlier  in  the  District  of  Columbia,  to  the 
third  week  in  Maj .  or,  according  to  Harris,  until  the  middle  of  June 
in  Massachusetts,  beginning  ;it  about  the  time  when  the  roses  first 
unfold  their  leaves  and  continuing  until  they  are  in  full  leaf.  During 
this  period  pairing  takes  place  and  eggs  are  deposited.  The  females 
are  particularly  sluggish  in  the  cool  of  morning  and  are  not  often  -ecu 
in  flight,  resting  during  the  greater  part  of  the  day  on  the  leaves. 
When  disturbed  they  draw  up  their  legs  and  fall  to  the  ground  The 
males,  however,  are  quite  lively,  flying  from  one  rose  hush  to  another 

and  hovering  around  their  less  active  partners. 

[Clr 


The  female  in  depositing  her  eggs  turns  a  little  in  one  side, 
unsheaths  her  delicate  saw-like  ovipositor,  and  thrusts  it  between 
the  two  cuticles  of  a  leaf,  depositing  a  single  vgg  in  each  incision.  An 
egg  is  shown  about  natural  size  at  <I.  figure  1.  and  much  enlarged  at  <. 
The  egg  i-  of  circular  outline,  much  flattened,  and  measures  about 
one-twentieth  of  an  inch  in  diameter.  Hatching  begins  in  from 
ten  days  to  two  week-  after  the  eggs  are  deposited. 

The  larva'  or  slugs  are  to  be  found  at  work  as  early  as  the  1st  of 
.May  in  the  District  of  Columbia,  but  their  appearance  in  number-  is 
seldom  noticed  until  the  second  or  third  week  of  that  month.  Obser- 
vations conducted  at  Washington,  1).  C.,  show  that  the  periods  men- 
tioned are  subject  to  considerable  variation.  In  L905  the  first 
sawflies  of  the  new  generation  appeared  June  2.  Owing  to  the 
irregularity  of  appearance  of  the  parent  "  flies.*'  larvae  of  the  first 
generation  may  be  found  at  work  for  a  period  of  live  or  six  weeks. 
Feeding  takes  place  chiefly  at  night,  and  always  on  the  upper  surface 
of  the  leaves,  the  lower  surface,  ribs,  and  midribs  remaining  as  a 
skeleton  (  fig.  1,  c).  The  leaves  are  practically  always  skeletonized, 
not  eaten  into  as  in  the  case  of  the  other  two  rose  slugs,  except  when 
the  larva'  are  nearly  grown.  During  the  daytime  the  larva  usually 
rest-  concealed  on  the  under  surface  of  a  leaf  (  fig.  2,  a). 

Sometimes  the  larva'  are  so  abundant  that  not  a  leaf  on  a  bush  is 
spared,  and  the  foliage  look-  as  though  it  had  been  scorched  by  fire, 
and  eventually  drops  off.  The  larva?  are  stated  to  be  between  two 
and  three  weeks  in  attaining  their  growth.  They  cast  their  skins 
several  times,  leaving  them  fastened  to  the  leaves.  After  the  last 
molting  they  lose  their  greenish  hue  and  become  opaque  yellowish. 
They  then  descend  into  the  earth  to  a  depth  of  an  inch  or  more,  and 
each  constructs  for  final  transformation  a  somewhat  fragile  oval  cell 
or  cocoon  coated  with  particles  of  earth.  Here  the  insect  remains  as 
larva  until  the  following  spring,  when  it  transforms  to  pupa  shortly 
before  issuance  in  May. 

The  species  i-  single-brooded,  in  which  respect  it  resembles  many 
other  species  of  sawflies." 

REMEDIES. 

This  rose  slug  and  the  others  which  will  be  discussed  are  quite 
easily  controlled  by  several  different  methods. 

Sprinkling  with  water. — A  strong  stream  of  water  directed  upon 
the  plants  from  different  sides  by  an  ordinary  garden  hose  or  large 

"  It   is  evident  from  Harris's  account    (I.  c.)   that  in  ascribing  two  generations 

to  this  rose  slug  he  must  also  have  had  the  bristly  rose  slug  under  observation. 
Miss  M.  E.  Murtfeldt  writes  on  tins  head  that  she  has  disproved  Harris's  state- 
ment "  by  repeated  rearing  of  the  insect  under  close  observation."     (41st  Annual 
Kept.  State  Hort.  Soc.  Missouri,  18'JS,  p.  2SS.) 
[CIr.  105] 


syringe,  if  applied  every  daj  or  two,  will  soon  rid  rosebushes  of  the 
pest,  rhia  is  ;ii  the  Bame  time  an  excellent  remedy  for  rose  aphidee 
or  plant  lice.  The  insects  are  dislodged,  fall  to  the  ground,  and  are 
unable  t"  return  to  reinfesl  the  bushes.  This  remedy  was  tested 
practically  by  Dr.  L.  O.  Howard  mam  years  ago. 

Pari  Where  it   is  possible  t<>  apply  them  without  danger 

of  poisoning  human  beings  or  disfiguring  the  plants  for  ornament, 
different  poisonous  preparations  are  useful.  Of  these,  Paris  green, 
cither  dry  or  in  solution,  arsenate  of  lead,  and  white  hellebore  are 
•  I  remedies.  Paris  green  is  best  used  as  a  Bpray  in  the  proportion 
of  an  ounce  iii  ;i  gallon  of  water.    Applied  dry,  it  is  mixed  with  •_'" 

part-  of  Hour  or  similar  diluent  and  puffed  on  the  plant-  by  mean-  of 
a  powder  bellows  or  insufflator.  For  use  in  large  gardens,  however,  the 
poison  is  employed  at  the  rate  of  1  pound  to  from  75  to  125  gallons 
of  water,  lime  being  added  in  about  the  same  proportion  as  Paris 
green  to  prevent  scorching.  For  properly  mixing  and  applying  this 
insecticide  a  -prayer  of  good  quality  should  be  used.  Sprinkling 
with  n  watering  pot  or  with  a  whisk  broom  will  n<»t  answer  the  pur 
po-e  and  is,  moreover,  dangerous  to  tender  foliage.  The  Pari-  green 
i-  first  mixed  with  n  small  quantity  of  water  into  a  fine  paste  before 
the  bulk  of  water  i-  added  and  should  be  churned  in  the  sprayer  or 
force  pump  until  thoroughly  blended.  The  resulting  mixture,  being 
a  mechanical  one.  i-  not  con-taut  and  the  arsenical  sinks  to  the  bo( 
torn.  The  solution  should  therefore  he  constantly  stirred  while 
being  applied  in  order  that  an  even  application  may  he  made.  In 
applying  an  arsenical  spray  an  effort  should  he  made  to  reach  all  of 
the  lea\e-.  which  may  he  accomplished  by  spraying  from  two  sides. 
Two  or  three  applications  will  suffice  for  the  spring  generation  of 
rose  slugs.  Scheele's  green  and  some  other  arsenicals  can  he  used 
instead  of  Paris  green. 

Arsenate  of  lead.  A  -till  more  valuable  insecticide  for  such  insects 
a-  rose  slugs  and  other  leaf  feeders  i-  arsenate  of  lead,  hut  it-  use  i- 
open  to  the  objection  that  it  di-color-  tin-  leafage,  leaving  a  white 
deposit,  which  is  not.  however,  permanent.  It  i-  applied  in  practi 
(•ally  the  same  manner  a-  Pari-  green  and  i-  a  less  poisonous  arsenical, 
and,  being  -old  in  paste  form,  i-  used  at  a  considerably  greater 
strength  about  1  pound  combined  with  15  to  25  gallons  of  water  or 
Bordeaux  mixture.  Being  adhesive,  it  adhere-  more  firmly  to  the 
leafage  and  is  much  less  likely  to  produce  scorching. 

Hellebore.     Hellebore  is  used  at  the  rate  of  l  ounce  to  from  2  to  :'. 
gallons  of  water,  and  kills  by  contact  a-  well  a-  by  it-  poisonous  effects 

■Additional  information  in  regard  to  the  preparation  and  use  ..f  arsenate  ••( 
lead  ami  other  Insecticides  is  given  in   Farmers'  Bulletin   127,  wblcb  may  be 
had  gratis  .»n  application  to  the  r.  s.  Department  of  Agriculture. 
[Clr  tor.] 


when  oaten  by  the  insect.  It  is  less  poisonous  to  man  than  an  arsen- 
ical, but  not  so  effective  to  leaf-feeding  larvae.  It  may  also  be  applied 
dry  mixed  with  about  double  its  weight,  or  more,  of  powdered  plaster 
or  cheap  flour. 

When  not  in  use  the  receptacles  containing  poisons  should  be 
plainly  labeled  "  Poison  !  "  and  placed  on  a  high  shelf  or  in  a  locker 
out  of  the  reach  of  children.  Properly  applied,  there  is  no  danger, 
in  using  an  arsenical  on  ornamental  plants,  of  poisoning  human 
beings,  or  domestic  animals  other  than  rabbits  or  similar  pets. 

Soaps  and  other  washes. — Oily  soaps,  such  as  fish-oil  or  whale-oil 
soap,  and  other  soaps,  and  tobacco  water  will  kill  these  insects,  but 
their  use  is  open  to  the  objection  that  if  applied  just  before  or  at 
blossoming  they  are  apt  to  injure  the  petals  of  delicate  flowers,  and 
whale-oil  and  tobacco  also  leave  an  unpleasant  odor.  A  neutral 
soap,  such  as  castile  or  that  used  by  physicians  and  surgeons,  leaves 
no  odor. 

Dry  powders. — Fine,  sifted  road  dust,  where  this  can  be  readily 
procured,  is  also  of  value  thrown  upon  the  plants,  preferably  by 
means  of  a  powder  bellows,  as  it  closes  the  breathing  pores  of  the 
larva?  and  thus  kills  them.  Finely  powdered  lime,  and  buhach  (Per- 
sian insect  powder,  or  pyrethrum)  are  also  effective. 

Hand  picking. — If  rose  slugs  are  picked  oil'  by  hand  upon  their 
earliest  appearance  this  will  greatly  reduce  their  numbers  for  the 
following  year.  In  the  adult  or  "  fly  "  stage  these  insects  may  be 
easily  captured  by  hand  on  cool  mornings.  Hand  picking  may  be 
tedious,  but  it  is  effective. 

Fall  cultivating. — If  other  means  that  have  been  specified  have  not 
been  utilized  for  the  suppression  of  the  slugs,  many  individuals  may 
be  destroyed  by  frequent  cultivation  of  the  soil  between  the  rose 
plants  during  the  late  summer  and  autumn.  This  has  the  effect  of 
breaking  up  their  pupal  cells  and  otherwise  disturbing  the  insects  so 
as  to  interfere  with  proper  hibernation. 

THE  BRISTLY  ROSE  SLUG. 

(Cladius  pectimcornis  Fourcr.) 

The  bristly  rose  slug,  called  also  the  spiny  rose  slug,  is  the  principal 
enemy  of  the  rose  in  and  near  the  District  of  Columbia,  not  excepting 
the  rose-chafer.  It  is  believed  to  have  been  brought  in  from  Europe 
some  time  prior  to  1833,  since  it  was  mentioned  by  Harris  in  his 
catalogue  of  Massachusetts  insects  of  that  date.  In  the  early 
seventies  it  was  reported  from  Connecticut  and  in  after  years  it  made 
its  way  westward  and  southward,  doing  more  or  less  injury  where- 
ever  established.  Since  1880  it  has  done  much  mischief  in  Wash- 
[Clr.  105] 


ington,  I  >.  ('.      In   1886  it  was  reported  from  Lafayette,  [nd.      In 
i  Was  ob  erved  to  be  injurious  a(  St  Charles,  Mo.     Soon  after 
wards  it   was  recognized  as  a   pe  <    it   St.  Louis,  where  ii  attracted 
considerable  nttention. 


hi  S(  RIPTION     \  M>   I » i  —  I  RIB!    I  los. 

The  adult  of  this  species  (fig.  3,  a)  differs  considerably  from  thai 
of  the  American  rose  slug,  as  will  be  readily  seen  by  a  comparison  of 
the  illustrations  of  the  two  forms.      It  is  ;i  larger  insed  and  u  mem 

ber  of  a  differenl  genus.    The  wing  »x | »:i 1 1-.-  is  ;il t  one-half  of  an 

inch  for  ili«'  female;  a  little  shorter  for  the  male.     The  ground  color 
i-  black.     The  antenna  are  rather  stoul  and  acutely  pointed,  and  in 


Fio.  :!      Brlet  -   {Cladtut  pectinicornU)     a,  Adult  female;  '-.  antenna  <>(  male; 

.-.  larva:  d,  head  of  same;  t,  female  pupa:  /. n      VII  enlarged.     (Reengrayed  after 

Riley,  except   •/.  original. 

the  male  the  proximal  joints,  or  those  nearesl  the  head,  are  pectinate 
or  comb-toothed  (fig.  3,  &),  which  has  given  rise  to  the  specific  name 
/-.  ctinu  ornis. 

The  egg  (fig.  I.  a)  is  white,  flattened,  rounded,  stoutest  at  the 
anterior  end,  and  more  pointed  at  the  opposite  end.    It  measures  about 

3  mm.  in  length. 

The  larva  or  slug,  shown  in  figure  '■"<.  c,  and  figure  1,  <.  </.  varies 
from  yellowish  to  glaucous  green,  and  the  whole  surface  is  quite 
bristly,  especially  at  the  sides,  a  character  from  which  this  larva  de- 
rive- its  common  name  and  which  will  distinguish  it  from  the  other 
two  that  feed  upon  the  rose.  The  length  when  full  grown  is  a  little 
[Clr.  106] 


more  than  three-fifths  of  an  inch  and  the  diameter  is  between  one- 
tenth  and  two-tenths  of  an  inch. 

The  pupa   (fig.  3,  e)  is  grayish  green,  the  thorax  and  end  of  the 
body  are  slightly  yellowish,  and  the  antennae,  wing-sheaths,  and  !• 
are  while  with  a  slighl   greenish   tinge.'' 

The  distribution  includes  the  States  of  Massachusetts,  Connecticut, 
New  York,  New  Jersey,  Pennsylvania,  Maryland,  the  District  of 
Columbia,  Indiana.  Illinois,  and  Missouri. 

It  is  generally  distributed  on  the  continent  of  Europe  and  occurs 
also  in   England  and  Scotland. 


Fig.   4.— Bristly   rose  slug    (Cladiua  pectinicornis)  ;  <i,   Egg;   h.   portion   of   leaf  showing 
eggs  in  situ  and  work  of  young  larva- :  c,  <i,  lateral   and  dorsal   aspects  of  midci' 
ment  of  newly  batched  larva  :  c,  larval  claw  ;  /,  rose  leaf  showing  nature  of  defoliation. 
All  except/  enlarged.     (Reengraved  after  Riley.) 


LIFE    HISTORY. 

The  bristly  rose  slug  differs  considerably  from  the  preceding  in  its 
life  economy.  Its  appearance  at  Washington.  D.  C.,  and  at  St.  Louis, 
Mo.,  has  been  observed  from  the  latter  days  of  April  to  the  third 
week  of  May,  beginning  about  the  time  that  the  first  rose  leave-  are 
put  forth.  Its  eggs  are  inserted  in  the  upper  surface  of  the  petiole 
of  the  leaf  and  are  deposited  in  rows  of  three  or  more  together. 

The  slug  in  its  earliest  stage  skeletonizes  the  leaves,  leaving  whitish 
blotches  and  small  holes  (fig.  4.  f),  but  with  increased  growth  it  eats 
large,  irregular  holes  in  the  leaf  (fig.  4.  &),  devouring  the  entire  sub- 

s More  detailed   descriptions  <>f   the   stages  are   furnished    in   C.    V.   Riley's 
article,   Insect  Life,   Vol.  V,  pp.  6-11,  which  includes  accounts  of  the  other  t\v<> 
species  here  treated. 
[Clr.  lor»] 


stance,  and  frequentl)  leaving  nothing  but  the  stronger  ribs.    While 
feeding,  the  slug  rests  in  concealment  on  the  lower  »ui*facc  of  :i  leaf, 
and  does  nol  feed  < >> i  the  upper  surface,  as  does  the    American  rose 
slug.     Upon  attaining  full  growth  ii  does  not,  like  the  latter,  aban 
■  Ion  (lie  plan!  upon  which  ii  has  fed  until  the  final  generation,     [ndi 
cations  are   thai    there   ma)    be   three  and,   in    -nun-  in    its 

southernmost  range,  perhaps  four  generations  produced  each  year, 
larva  occurring  as  earl)  as  the  1st  of  Ma)  and  as  late  as  the  Isi 
lit'  November.  In  northern  Europe  two  generations  are  recognized." 
The  larvae  of  the  earlier  generation  spin  their  cocoons  ( fiir.  3,  />. 
which  are  composed  parti)  of  silk  and  parti)  of  a  glutinous  sub 
stance,  upon  the  lower  surface  of  the  leaves,  or  mi  twigs  or  near  by 
objects,  usually  surrounding  them  w  ith  an  irregular  fringe.  The  lasl 
or  autumn  generation  forms  it-  cocoons  among  fallen  leaves  and  other 
rubbish  about  the  base  of  the  rose  bushes. 

The  egg  period  in  late  April  and  early  in  May  has  been  observed 
in  the  District  of  Columbia  to  last  for  from  seven  to  ten  days,  and 
the  young  larva?  begin  feeding  in  tin'  lir-t  and  second  weeks  of  May. 

I  .mi  \  re  grow  rapidly,  and  cocoons  have  been  Ion  mi  by  the  middle  of 
May.  The  pupal  peri  ml  observed  was  fifteen  da)  .  so  thai  the  second 
brood  of  flies  may  appear  before  the  end  of  May.  This  second  g 
eration  begins  work  about  the  second  week  in  June,  l>ut  during  July 
there  is  a  comparative  cessation,  presumably  between  the  second  and 
third  broods  of  worms,  when  fresh  growth  is  little  affected. 

Mr.  (I.  Paul-.  St.  Louis  Altenheim,  St.  Louis,  Mo.,  wrote  in  re{ 
to  observations  conducted  by  him  on  this  species  at  St.  Louis  in  1904. 
The  sawfly  continued  depositing  eggs  up  to  September  17.     October 

II  he  placed  larvas  in  a  jar:  three  transformed  to  pupa'  October  17. 
l!'.  and  •_' I  and  issued  March  30  to  April  10  of  the  following  year. 
One  larva  pupated  October  16  and  issued  March  •_'_'.  having  passed 
about  five  months  in  the  pupal  stage.  This  shows  considerable  varia- 
tion in  tlu'  time  of  issuing  indoor-,  and  would  probably  be  duplicated 
to  a  certain  extent  in  the  open.  April  •_"•>  he  observed  the  sawfl) 
depositing  eggs  on  the  have-. 

,  \  vrt   RAl     ENEMIES. 

No  natural  enemies  of  tin-  rose  -Inn-  appear  to  have  been  recog- 
nized in  America,  hut  in  Europe  it  i-  preyed  upon  by  two  paras 
Acrotomus  luciduliu  Grav.  and  Mesochorus  cimbicu  Uat/. 

■Various  European  authors  have  written  en  this  species.  One  <>f  fin-  most 
accessible  general  articles  is  thai  by  M.  s.  <\  Snellen  van  Vollenboven,  trai 

lated  from  i  he  Dutch  by  J.  W.  May  and  nuulisbed  iu  The  Entomologist,   Vol. 
vill.  is?.".,  pp.  26  -  ■• 
[Clr.  lor.] 


10 

REMEDIES. 

The  same  remedies  advised  against  the  American  rose  slug  are  em- 
ployed against  the  presenl  species,  with  the  exception  of  fall  cultiva- 
tion, which  is  practically  useless  when  applied  to  it,  owing  to  the 
fact  that  the  cocoons  are  formed  upon  the  plants  on  the  surface  of 
the  ground  and  not  buried  in  the  earth  as  with  the  preceding  specif-. 
Since  there  are  more  than  one  generation  of  this  slug,  sprinkling 
with  water  and  spraying  with  poisons  must  be  repeated  several  tin 
in  order  to  produce  the  desired  results:  in  short,  as  often  as  the 
insects  reappear  upon  the  plants,  from  April  to  October,  according  to 
locality. 

THE  COILED  ROSE  SLUG. 

(Emphytua  cpnetus  L.°) 

The  third  of  the  rose  slugs  under  consideration,  the  coiled  rose 
slug,  is  a  comparatively  recent  importation.  As  with  the  two  pre- 
ceding species,  it  first  attracted  attention  near  Boston,  Mass.,  but 
not  until  the  year  1887.''  It  is  probable,  however,  as  in  the  case  of 
most  European  insects  introduced  into  this  country,  that  its  importa- 
tion was  accomplished  at  a  considerably  earlier  date.  Reasoning 
from  analogy,  this  insect  might  have  been  brought  from  the  mother 
country  on  potted  roses  ten  or  twenty  years  earlier  than  the  date 
specified,  as  that  length  of  time  is  sometimes  necessary  for  a  foreign 
insect  to  become  permanently  established  so  as  to  attract  attention 
by  its  injuries. 

DESCRIPTION    AM)    DISTRIBUTION. 

From  the  two  preceding  species  this  insect  may  be  readily  sepa- 
rated on  account  of  its  larger  size  in  the  adult  stage  (fig.  •*>.  a).  It  has 
nearly  transparent  wings,  and  a  wide  band  which  crosses  its  shining 
black  abdomen  near  the  middle.  The  body  is  comparatively  slender, 
and  the  head  longer  than  in  the  other  two  species.  The  wing  expanse 
is  about  five-eighths  of  an  inch  and  the  length  of  the  body  about  three- 
eighths  of  an  inch. 

The  larva  when  mature  is  about  three-fourths  of  an  inch  long  and 
differs  notably  from  the  other  two  species  here  considered  in  being 
perfectly  smooth.  It  is  cylindrical  and  tapers  very  slightly  toward 
the  posterior  extremity.  The  color  is  metallic  green  above,  orna- 
mented with  small  white  dots,  and  the  lower  surface,  including  the 
legs,  is  grayish  white.  The  head  (fig.  5,  c)  is  yellowish  orange,  with 
a  dark  brownish-black  stripe  down  the  middle.     The  eyes  are  black. 

°  Emphytus  cinctipes  Nort.  is  recognized  ;is  a  synonym. 
».T.  G.  Jack.  Garden  and  Forest,  Mar.  26,  1890,  pp.  151-152. 
[CIr.  10r>] 


II 


The  tii -i  thoracic  segment  is  ' •  1 1 1«-  and  the  las!  two  are  gi  The 

larva   habitually   rests   in   the  coiled   or  curled   position   shown   in 
figure  •">,  6,  one  that  is  never  assumed  by  either  of  the  other  rose  slugs, 

and  it  is  from  this  habil  thai  it  der  English  m 

In  addition  to  Boston,  it  has  been  authentically  reported  from 
Jamaica  Plain,  Roxbury,  and  Nev  Bedford,  Mass.;  portions  of 
Mimic;  Allegheny,  I'a.:  Nev  York,  and  Canada.  In  the  Eastern 
Hemisphere  this  species  ranges  over  the  major  portion  of  Europe, 
extending  int<>  Siberia. 

NATURAL    HISTORY. 

The  coiled  rose  slug  is  credited  with  being  double-brooded,  and  as 
it  extends  it-  range  southward  it  will  probably  produce  a  third  gen- 
eration, since  we  know  of  the  appearance  of  the  "  worm  "  from  May 


i"i.;    5      Colled  rose  Blug   {Bmphytua  cinctua)  :  a,  Adull    fei  Full  grown   larva;  ■  . 

head  of  same;  ''.  work  on  plant  :  t,  <.  young  Ian  ;  >/.  '>. 

enlarged;  c,  more  enlarged.     (Reengraved  aftpr  Riley.) 

to  October.  Eggs  are  deposited  singly  on  the  underside  of  the 
leave-  to  the  observed  number  of  from  three  t<>  -even.  This  slug 
differs  from  the  other--  in  devouring  the  entire  substance  of  a  leaf. 
feeding  along  the  edges  with  it-  bodj  roiled  beneath  it.  and  when  al 
resl  remaining  curled  in  a  ball  on  the  lower  surface  (see  1  i ir.  5,  e). 
Upon  reaching  maturity  the  slug  deserts  the  leave-  and  bores  into 
the  pith  of  the  stems  of  dead  rose  bushes  or  other  available  plants, 
and  here  the  pupal  state  is  passed,  the  fall  generation  hibernating  to 
emerge  the  following  May.  At  Boston,  Ma—,  the  adults  have  also 
been  observed  in  duly,  this  indicating  the  first  new  generation. 

\    more  technical   description   by    I>r.   II.   <;.   Dyar   is  given   in   the  Canadian 

Entomologist,  VoL  XXVI,  p.  160. 

[Cir.  105] 


UNIVERSITY  OF  FLORinA 

12        ■illffillllll 

3  1262  09216  5298 

NATURAL    KM.  M  iks. 

A  parasitic  enemy  of  this  species  was  reared  by  the  writer  from 
larva-  received  from  Allegheny,  Pa.,  in  1904.  It  issued  October  20, 
and  proved  to  he  a  tachina  fly,  Tachina  rustiea  Fall. 

In  Europe  an  ichneumon  fly,  Cryptus  emphytorum  Boie.,  is  para- 
sitic upon  this  sawllv. 

REMEDIES. 

The  remedies  are  the  same  as  for  the  American  rose  slug,  subject, 
however,  to  the  same  changes  as  for  the  bristly  rose  slug. 

Approved : 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  I).  C,  August  .',.  1908. 

[Cir.  lor, J 

o 


